Ciiauncey n



on E. (Application filed Aug; 12, 1897.)

\ ll l I W/TNESSES/ Patenfed Mar. 2!, I899. C. N. DUT TRUSS UNITED STATES PATENT OFFICE.

euAUNe v N.-DUTTON,, on NEW YORK, N. 'Y.

TRuss OR FRAME.

srncrn rcn'rzon mrinnrgqsmermttersrawnt norcziao xnatenmmai, 1899. p I Application iiledAugnst 12,1897. Serial No. 647,991: (No model.)

' Toall whom it may concern:

.- .Be it known .that I, CHAUNCEY N. Du'rron, of the city, county, and State of New York, have invented a certain new and useful Im- 5 p'rovementin Trusses or Frames, of which -improvement thefollowing is a specification.

The object'of my invention is to provide atruss orbracedframe for use in buildings, bridges, doehs, prother structures in which lo a load, either permanent orinterinitteiit; is't'o be supported, in which truss all the web members shall be in compression and one chord s only in tension. V

To this end my invention, generallystated, Q1 5 consists in the combination of an inwardly curved or bent upper chord member, a lower chord member curved in the same direction,

. 'endconnections-uniting the chord members,

2o chord members.

' 1 -wsnd- Webmembers -Iut'erposed" betweeir'tne' fully set forth... l i

- In the accompanying drawings Figures 1' and 2 are side views illustrating trusses em- .25 bodyingmy invention. ,4 Referring first more particularly to the combination shown in Fig. 1, which is designed, primarily, for a timber construction for uniform or central load, in the practice of my invention I provide an upper chord member 1 and a lower chord member 2, each of which is preferably.. of timber. 'The upper chord member is inwardly. or downwardly'curved or bent on a segment of a circle of comparatively large radius or in a series of connected chords of arcs and the lower chord member is curved in the same direction, but on a shorter radius. The upper and lower chord members are connected adjacent to their ends in substantially the form of a crescent-in this instance by keys 3=-and are held apart intermediately of their connections by interposed web members or struts 4. The truss rests at or near its ends on rigid supports or abutments 5. Under'such construction the lower chord member only is in tension and the upper chord and web members are compression members.

When load is applied to the truss, its tendency is to curve the truss into a sharper crescent, the web members or struts holding the chord members a fixed distance apart, so

'If it sprung toward. the lower chord member,

'beam adapted to use as a buffer or spring.

' should be replaced or supplemented by a stiff that their moments are a uniformratio. The upper chord member is necessarily ina curved or broken line convex toward the lower chord member, since if it were concave toward the lower chord member the web members would be in tension and their joints with the chord members would necessarily be in tension, which is undesirable in a purely timber structure. If the upper chord members were straight, the strains would be uncertainand would depend upon the chance ofthe'upperchordspringing in one or the' other direction.

S the strains wodld be compressed, while, as would probably be the case when the load was applied to the lower member,if it sprung away from the lower member. the web members would be in tensigngvhich possibility ispre'. chided 5y 'tl'fdconstrnctiondescribed and shown.

-F-ig..2 illustrates the application of the essential features of my invention in an elastic To this end the web members are formed of springs 4, which maybe either helical,- as shown, orof any other preferred type, and the simple key connection shown in Fig. 1

plate or plates 3 at each end, to which the chord members are connected by bolts 6, and

the ends should be confined so that the truss cannot spring backward. This is preferably eifected by means of adjustable gibs 7, fitting on bed-plates 8 on the piers or sppports 5, and the ends of the truss are provided with bearing-plates 9, abutting against the bed-plates and gibs, so that the truss can shorten and lengthen as its lead is increased or decreased or when it 'is subjected to shock.

I claim as my invention and desire to Se. cure by Letters Patent- 1. In a truss or frame, the combination of an outwardly-convex tension-chord, a compression-chord curved in the-same direction, connections uniting the chord members, and compression 'web members interposed between the chord members.

2. In a truss or frame, the combination .of an outwardl-ysconvex tension-chord member, a compression-chord member curved in the same direction, end connections uniting the chord members, and spring compression web members interposed betweehjthe'cherd mem; bers. 4

Cdmpos'ed of an -ol 1tward1y-convex pension 5 chord member, a. compressionchord member 3. Thecombination'of a Lrussnrfframe,

hed-piat'es seemed "thereto; and adjhstable' I 'I members interposed between the truss and 10 said"bed-plates.., H:

Y 3 v TULEs' P. METZGER; f 3 

